Citation Antibiotic resistance is ancient. D’Costa Vanessa, Christine E. King, Lindsay Kalan, Mariya Morar, Wilson W.L. Sung, Carsten Schwarz, Duane Froese, Grant Zazula, Fabrice Calmels, Régis Debruyne, Brian G. Golding, Hendrik N. Poinar, Gerard D. Wright. Nature 2011, 477(7365):457-461. DOI: 10.1038/nature10388